FEL SPEED

[flINTLOCK]

I posted this question on the NH section and didn't get any takers. So, thought I'd try again, since it's a generic question that applies across all makes and models. I found that it was difficult to accurately position my new grapple due to fast up/down function of FEL. I'm sure I'll get better with more hours of practice. Since I'm going to be using FEL much more with grapple moving logs and large rocks, would it make sense to put a reducer fitting in the FEL circuit to slow it down?? My understanding is that it would not affect lift capacity, but simply rapidity of motion??

 

[Tom_Veatch]

...would it make sense to put a reducer fitting in the FEL circuit to slow it down?? My understanding is that it would not affect lift capacity, but simply rapidity of motion??

I'm not a hydraulic systems expert, and can't comment on what all the practical consequences might be, but from a theoretical fluid flow standpoint your understanding is correct depending on the definition of "lift capacity".

The pressure drop across a restriction is a function of the flow rate through the restricting orifice, all other things being the same. So at any given pressure, the flow rate with the restriction will be less than it would be without the restriction. The energy lost will reappear as additional heat in the fluid. That may, or may not, be a consideration in your application.

At zero flow rate, the pressure at the ram or cylinder will be the same with or without the added restrictor. Thus the static force applied by the cylinder/ram will be the same in either case. If that is the definition of "lift capacity", then there is no change due to the added restriction. However, there must be some flow rate in order to move the load. That means some pressure will be lost to the restriction - the greater the flow rate or the faster the load is moved, the higher the pressure loss.

Saying this in another way, with an added restriction in the circuit, the effect will be that for a given speed of movement, the maximum load that can be moved will be less. For a given load, the movement speed will be less. Whether this effect will be noticable or significant in your particular case is open to question.

Is there some way to safely insert a variable orifice, i.e. valve, in the flow so that you could throttle down the flow rate as needed, and restore full flow if/when required?

 

[JerryG]

Is it the grapple or the loader that is to fast?

 

[flINTLOCK]

Loader is difficult to "feather" into position so that grapple can approach target optimally. Grapple function is fine. Put 1/4" hoses on it.

 

[john_bud]

Loader is difficult to "feather" into position so that grapple can approach target optimally. Grapple function is fine. Put 1/4" hoses on it.

You should be able to flip open a sandwich with the bucket lip (with practice). If you can't, it's either a case of more practice - and gentle touch needed or possibly the control is sticking. Go to the dealer and Test Drive a similar model and see if it is the same.

A quick way to smooth out the feather speed is to lower the rpm's down to idle and then slowly raise up into position. Then clamp and go.

jb

 

[rback33]

What RPM are you operating at while trying to accomplish this? If you are using a hydro with the RPM's up, bump them back to get less flow and you will have more control. Gear tractors are easier for this kind of problem because you can use the foot throttle for everything.

 

[3RRL]

I'm thinking you should be able to "feather" the fel valve via the joystick control? Moving your joystick less than full in any direction should result in slower fel speed. The less you move it, the slower the function. That action is reducing/restricting the flow to those cylinders. It is a built in flow restriction controlled by your hand. That is also the reason I don't like flow restrictors in the system because you lose the full speed when you want it.

 

[_RaT_]

I'm thinking you should be able to "feather" the fel valve via the joystick control? Moving your joystick less than full in any direction should result in slower fel speed. The less you move it, the slower the function. That action is reducing/restricting the flow to those cylinders. It is a built in flow restriction controlled by your hand. That is also the reason I don't like flow restrictors in the system because you lose the full speed when you want it.

I was thinking much the same. By feathering the FEL spool, you are in effect, restricting the flow. I have yet to see a spool for a loader that is all on or all off. I have quite a different issue. The 3rd party loader on a NH TC 33 I am using is so slow and the ability to dump the bucket and lower the boom is all but impossible. It drives me nuts to use such a slow loader, especially the dump circuit which takes a couple days to get to the fully dumped psoition. I think I'm spoiled.

 

[MikePA]

Dupe with this thread posted 2 hours earlier.